1. Field of the Invention
The present invention relates to an eyeglass frame shape-measuring apparatus that measures a lens frame shape of an eye glass frame.
2. Description of the Related Art
Conventionally, an apparatus for measuring an eyeglass frame shape is known (for reference, see JP3695988B). The apparatus predicts variations of a moving radius of an unmeasured part based on changes in information of an already measured moving radius. Then the apparatus controls driving of a drive motor in correspondence to the predicted variations of the moving radius. Next, the apparatus changes a pressing pressure of a feeler that measures a shape of an eyeglass frame. Hereby, the term “moving radius” means changes in distance from a geometrical center or optical center of the eyeglass frame to a periphery of an internal side of the eyeglass frame.
However, in such a conventional apparatus for measuring eyeglass frame shapes, a method is adopted in which variations in a moving radius of an unmeasured part are predicted based on changes in information of an already measured moving radius. This method is fine in the case if the moving radius of the unmeasured part changes as predicted. But as a variety of shapes of eyeglass frames have recently emerged, there are cases in which the moving radius changes in a direction that differs from prediction. Therefore, in the case the moving radius changes in a direction that differs from prediction, it is problematic that the pressing pressure changes in a direction that reversely deforms the eyeglass frame so that shape measurement is possibly not correctly done.